// https://www.lintcode.com/problem/unique-characters/

public class Solution {
    /*
     * @param str: A string
     * @return: a boolean
     */
    public boolean isUnique(String str) {
        // write your code here
        for (int i = 0; i < str.length(); ++i) {
            for (int j = 0; j < str.length(); ++j) {
                if (i != j) {
                    if (str.charAt(i) == str.charAt(j)) {
                        return false;
                    }
                }
            }
        }
        return true;
    }
}